A para-to meta-Isomerization of Phenols

Jean-Philip Lumb describes a new method to isomerize phenols in a chemo- and regioselective manner.

Phenols are a common functional group of many important molecules, including the amino acid tyrosine and its many derivatives, secondary metabolites from across the tree of life, and a plethora of industrial chemicals, including many that are essential to pharmaceutical, agrochemical and materials industries. Phenols are defined by an aromatic ring with a hydroxyl substituent, whose properties are intimately linked to neighboring substituents. Phenol isomers localize electron density differently, have different dipoles, acidities, redox potentials, and abilities to engage in hydrogen bonding or π-interactions. The resulting substituent effect could be strategic to explore as a ‘late-stage’ or ‘peripheral’ modification, but a phenol isomerization faces several formidable challenges. According to Professor Jean-Philip Lumb from McGill University (Canada) “there are only two related examples in which the substituents of a phenol, namely substituents other than the –OH group, were isomerized, but both methods required forcing conditions and exhibited limited scope.” In this work, Professor Lumb and his PhD student Simon Edelmann have developed a method to isomerize phenols, which should facilitate the synthesis of isomers that could otherwise be difficult or costly to prepare.

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